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Prizoop v 1.1

Prizoop is a Game Boy and Game Boy Color emulator for the Casio Prizm series graphing calculator, with intense focus on optimization and decent feature set for the target device. As such, it is not a very accurate emulator but is very fast and compatible. The emulator now supports fx-CG10, fx-CG20, and the new fx-CG50.

It got its name because it started out as a fork of the multiplatform Game Boy emulator, Cinoop, by CTurt. It has since undergone an almost total rewrite and shares some of the cpu code, organization and constructs from Cinoop, but for the most part resembles Cinoop much less than a normal fork.


Copy the prizoop.g3a file to your Casio Prizm calculator's root path when linked via USB. Gameboy and Gameboy Color roms (.gb and .gbc) also should go inside of the root directory. The filenames for these files should be simple and less than 12 characters, such as MyGame.gbc.

Additionally, Windows users can compress a .gb and .gbc ROM file into a smaller .gbz file that is also compatible, though the game will be slightly slower when starting a new level, etc due to needing to decompress data on the fly. Some games such as Ghosts and Goblins will compress to ~10% of their original size, enabling you to have a much larger library on your calculator. To compress a ROM file, simply run comp-gb.exe and select the ROM to compress. The tool will automatically create a .gbz file in the same folder.



In the menu system use the arrow keys and SHIFT to select.

  • F1: Select ROM
  • F2: Settings (most are self explanatory)
  • F5: FAQ Viewer
  • F6: Play ROM (it will first show diagnostic information)

When inside a game, the MENU key will exit to the settings screen, and pressing MENU again will take you back to the calculator OS.

A single save state is supported per ROM, which can be loaded/saved using the remappable keys mentioned in the Controls section.

In Game

You can configure your own keys in the Settings menu, these are the default I found to work well:

  • Dpad : Dpad
  • A: SHIFT
  • B: OPTN
  • Select: F5
  • Start: F6
  • Save State : X (multiply), which is the alpha 's' key for save
  • Load State : -> (store), which is the alpha 'l' key for load
  • Increase Volume/Distortion : +
  • Decrease Volume/Distortion : -

Some games, such as the Mario titles, play much better with a reversed control scheme, where you bind left and right to Shift/Option, and A and B to Cos/Tan. This is because the Prizm directional pad is a little flaky and on the opposite side as a traditional game controller.

FAQ Viewer

FAQ View

If you have a text file (.txt) with the same base filename as any of your ROM's, this text file can now be viewed inside of Prizoop for easy reference. The FAQ is viewed with a calctype font (see my other repo) that is a clear and easy to read text at just 5 pixels wide per character. To read the FAQ, just use the new FAQ option from within the menu. Prizoop will save your most recently viewed FAQ position to make it simple to go back and forth with the game and between sessions.

Many game FAQs are built to wrap short lines (around 80 characters) and these will display with no trouble on the calculator. Many international characters are supported, but make sure your .txt file is saved in ANSI text format. UTF formats are not supported.

FAQ viewing controls:

  • Up / Down: Scroll up and down
  • Left / Right : Shift left and right (useful for badly wrapping FAQ files)
  • F2: Game settings
  • F6: Return to Game


Game Banner

The emulator now plays over 95% of the games I have been able to test smoothly at this point. Some games where timing accuracy is very important suffer, specifically racing games. Road Rash and F1 Race are playable but have some visual issues, and F1 Pole Position does not play at all. Pokemon Rouge (the French Pokemon Red) now officially works.

The emulator now supports Real Time Clock games such as Pokemon Gold and Silver, utilizing the real time clock on the Prizm.


The emulator has full support for sound, though it is somewhat limited due to the 1-bit nature of the Prizm serial port. If you have a 2.5 mm to 3.5 mm headphone adapter, you can enjoy low-lag sound with a decent frequency range in one earphone (left or right, depending on the adaptor). Some adaptors seem to have different voltage output, so you may get some distortion or unusually high volume. Volume and distortion can be simultaneously adjusted with the + and - keys.


My other repository, PrizmSDK, is required to build Prizoop from source. Put your Prizoop clone in the SDK projects directory.

To build on a Windows machine, I recommed using the project files using Visual Studio Community Edition, where I have NMAKE set up nicely. For other systems please refer to your Prizm SDK documentation on how to compile projects. Refer to the configuration options in make-DeviceRelease.bat.

If you do use Visual Studio, a project is included that uses a Windows Simulator I wrote that wraps Prizm OS functions so that the code and emulator can easily be tested and iterated on within Visual Studio. See the prizmsim.cpp/h code for details on its usage.

Special Thanks

BGB was a huge part of bug fixing and obtaining decent ROM compatibility. It is a Gameboy emulator with great debugging and memory visualization tools:

A huge special thanks obviously goes to CTurt, who's simple explanations and easy to read source got this project rolling by making it seem much less scary. See the original Cinoop source code here:


Gameboy and Gameboy Color emulator for Casio Prizm






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